# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Cedar Creek
Water Body ID: | CAR6412004020020529113658
Water Body Type: | River & Stream

DECISION ID | 21788 | Region 6
Cedar Creek

Pollutant: | Chloride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeded the Maximum Contaminant Level. The annual average site-specific objective was exceeded in three out of three years. Annual average datapoints were calculated based on only 2 to 3 samples per year. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Non of 8 samples exceeded the MCL. Three of three annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21788, Chloride | Region 6
Cedar Creek
LOE ID: | 4974
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 8 chloride samples between 2003 and 2005 under the Region 6 SWAMP program. Chloride concentrations ranged from 4.35 to 8.13 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples were collected over 3 years (2 to 3 samples/year between 2003 and 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. Chloride concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21788, Chloride | Region 6
Cedar Creek
LOE ID: | 4826
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 8 chloride samples between 2003 and 2005 under the Region 6 SWAMP program. Chloride concentrations ranged from 4.35 to 8.13 mg/L. Calculated annual average values exceeded the objective in three of three years.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific chloride objective for Cedar Creek (Lahontan Basin Plan Table 3-7) is an annual average of 1 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples were collected over 3 years (2 to 3 samples/year between 2003 and 2005). Three annual average calculations were done.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. Chloride concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21268 | Region 6
Cedar Creek

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the datsets used satisfies the data quality requirements of section 6.1.4 of the Policy. No quality assurance information was available for the other dataset. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. One or two samples are not representative of the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of three samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21268, Dissolved oxygen saturation | Region 6
Cedar Creek
LOE ID: | 6356
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one sample on August 13, 2002. Percent saturation of dissolved oxygen was 81 percent. The objective was not violated.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide narrative objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, Upper Cedar Creek.
Temporal Representation: | One sample was collected on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the U.S. Bureau of Land Management data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21268, Dissolved oxygen saturation | Region 6
Cedar Creek
LOE ID: | 5724
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek under the Region 6 SWAMP program. Two measurements of percent saturation, taken in October 2004 and July 2005, were 102 and 103 percent. The objective was not violated.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide narrative objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Two percent saturation samples were collected in October 2004 and July 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21253 | Region 6
Cedar Creek

Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Two of the samples in the SWAMP dataset exceed the water quality objective. The single sample in the U.S. Bureau of Land Management dataset exceeds the objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. No quality assurance information was available for the other dataset. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples do not reflect the expected seasonal and annual variability in fecal coliform concentrations in waters of the Lahontan Region. The BLM data include only one fecal coliform sample. The water quality objective calls for five samples to be collected in a 30 day period. 3. Two of seven samples in one dataset, and the single sample in the other exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21253, Fecal Coliform | Region 6
Cedar Creek
LOE ID: | 6375
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one sample in August 2002. The fecal coliform count was 45 colonies per 100 mL, exceeding the limit in the objective.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, "Upper Cedar Creek."
Temporal Representation: | One sample was collected on August 13, 2002..
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Management owns land in the lower watershed.
QAPP Information: | No information on quality assurance was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21253, Fecal Coliform | Region 6
Cedar Creek
LOE ID: | 5687
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 7
Number of Exceedances: | 2
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek under the Region 6 SWAMP program between 2003 and 2005. The fecal coliform counts in five of seven samples were estimates or below detection levels. Counts in the two remaining samples were 22 and 80 colonies per 100 mL.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Seven samples were collected between 2003 and 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21253, Fecal Coliform | Region 6
Cedar Creek
LOE ID: | 5686
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 7
Number of Exceedances: | 2
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek under the Region 6 SWAMP program between 2003 and 2005. The fecal coliform counts in five of seven samples were estimates or below detection levels. Counts in the two remaining samples were 22 and 80 colonies per 100 mL.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Seven samples were collected between 2003 and 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21253, Fecal Coliform | Region 6
Cedar Creek
LOE ID: | 6374
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one sample in August 2002. The fecal coliform count was 45 colonies per 100 mL, exceeding the limit in the objective.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, "Upper Cedar Creek."
Temporal Representation: | One sample was collected on August 13, 2002..
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Management owns land in the lower watershed.
QAPP Information: | No information on quality assurance was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21941 | Region 6
Cedar Creek

Pollutant: | Nitrate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples and the single BLM sample do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 8 samples in one line of evidence or the single sample in the other exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21941, Nitrate | Region 6
Cedar Creek
LOE ID: | 5373
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one sample in August 2002. The NO3-N concentration in one sample was 0.09 mg/L. The MCL was not violated
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate", equivalent to 10 mg/L expressed "as nitrogen."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, "Upper Cedar Creek."
Temporal Representation: | One sample for nitrate nitrogen was collected on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21941, Nitrate | Region 6
Cedar Creek
LOE ID: | 7545
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek between 2003 and 2005 under the Region 6 SWAMP program. One of eight quarterly samples for nitrite plus nitrate was below the detection level. Concentrations in the remainder of the samples ranged from 0.001 to 0.261 mg/L. The combined total values did not exceed the MCL for nitrate.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate." This is equivalent to 10 mg/L expressed "as nitrogen."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Eight samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight quarterly samples for nitrite plus nitrate were collected between 2003 and 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21942 | Region 6
Cedar Creek

Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 8 samples exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21942, Nitrate/Nitrite (Nitrite + Nitrate as N) | Region 6
Cedar Creek
LOE ID: | 7539
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek between 2003 and 2005 under the Region 6 SWAMP program. One of eight quarterly samples for nitrite plus nitrate was below the detection level. Concentrations in the remainder of the samples ranged from 0.001 to 0.261 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L expressed "as nitrogen."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight quarterly samples for nitrite plus nitrate were collected between 2003 and 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21943 | Region 6
Cedar Creek

Pollutant: | Nitrite
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 8 samples exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21943, Nitrite | Region 6
Cedar Creek
LOE ID: | 7547
Pollutant: | Nitrite
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek between 2003 and 2005 under the Region 6 SWAMP program. One of eight quarterly samples for nitrite plus nitrate was below the detection level. Concentrations in the remainder of the samples ranged from 0.001 to 0.261 mg/L. The combined total values did not exceed the MCL for nitrite.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is 1 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Eight samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight quarterly samples for nitrite plus nitrate were collected between 2003 and 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 20741 | Region 6
Cedar Creek

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence from different datasets are available in the administrative record to assess this pollutant. The lines of evidence have not been grouped because dissolved oxygen measurements in the two studies may have been taken using different equipment, and one of the datasets was submitted without quality assurance information. One of the samples in the latter dataset exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. No quality assurance information was submitted with the second dataset. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples and the single USBLM sample do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of six samples in one line of evidence exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. The other line of evidence consisted of one sample, which exceeded the objective. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20741, Oxygen, Dissolved | Region 6
Cedar Creek
LOE ID: | 4828
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 6
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey took six dissolved oxygen measurements between 2003 and 2005 under the Region 6 SWAMP program. The minimum concentration was 8.6 mg/L. The objective was not violated.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The 1 day minimum objective for waters designated for the Cold Freshwater Habitat and Spawning, Reproduction and Development uses is 8 mg/L (Lahontan Basin Plan Table 3-6).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Six samples were collected over 3 years (2 to 3 samples/year between 2003 and 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 20741, Oxygen, Dissolved | Region 6
Cedar Creek
LOE ID: | 5370
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one dissolved oxygen sample at Cedar Creek in 2002. The dissolved oxygen concentration in one sample was 7.8 mg/L, in violation of the objective.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The 1-day minimum objective for waters designated for the Cold Freshwater Habitat and Spawning, Reproduction and Development uses is 8 mg/L (Lahontan Basin Plan Table 3-6).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Upper Cedar Creek".
Temporal Representation: | One sample was collected in August 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21841 | Region 6
Cedar Creek

Pollutant: | Phosphate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence, each consisting of a single phosphate sample, are available in the administrative record to assess this pollutant. There are no numerical phosphate objectives for this stream. No biological data are available to determine whether of the samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the lines of evidence satisfies the data quality requirements of section 6.1.4 of the Policy. The other does not. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Only one sample was available in each dataset. 3. It is not possible to determine whether the biostimulatory substances objective was exceeded. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21841, Phosphate | Region 6
Cedar Creek
LOE ID: | 7559
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected one dissolved phosphate sample under the Region 6 SWAMP program in March 2004. The PO4-P concentration was 0.034 mg/L No data on algae or macrophytes are available to allow assessment of compliance with the narrative biostimulatory substances objective..
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include site-specific objectives for phosphorus for Cedar Creek. The regionwide narrative objective applies. It states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Sampling was done at one station, Cedar Creek near Cedarville.
Temporal Representation: | One sample was collected on March 24, 2004.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. In addition to the Cold Freshwater Habitat beneficial use, Cedar Creek is designated for the Spawning, Reproduction and Development use..
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21841, Phosphate | Region 6
Cedar Creek
LOE ID: | 5381
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management collected one sample in 2002. The PO4-P concentration was 0.028 mg/L No data on algae or macrophytes are available to allow assessment of compliance with the narrative biostimulatory substances objective..
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include site-specific objectives for phosphorus for Cedar Creek. The regionwide narrative objective applies. It states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Sampling was done at one station, "Upper Cedar Creek."
Temporal Representation: | One sample was collected on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. In addition to the Cold Freshwater Habitat beneficial use, Cedar Creek is designated for the Spawning, Reproduction and Development use..
QAPP Information: | No quality assurance information was submitted with this dataset.
QAPP Information Reference(s):

DECISION ID | 21883 | Region 6
Cedar Creek

Pollutant: | Phosphorus
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological information is available to assess whether the 8 total phosphorus samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples.. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Because of the lack of biological data, it is not possible to determine whether the water quality objective was exceeded. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21883, Phosphorus | Region 6
Cedar Creek
LOE ID: | 4833
Pollutant: | Phosphorus
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek between 2003 and 2005 under the Region 6 SWAMP program. Concentrations of total phosphorus in 8 samples collected over 3 years ranged from 0.39 to 0.128 mg/L. No data on algae or macrophytes are available to allow assessment of compliance with the narrative biostimulatory substances objective..
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include site-specific objectives for phosphorus for Cedar Creek. The regionwide narrative objective applies. It states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples were collected over 3 years (2 to 3 samples/year between 2003 and 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. In addition to the Cold Freshwater Habitat beneficial use, Cedar Creek is designated for the Spawning, Reproduction and Development use..
QAPP Information: | Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. .
QAPP Information Reference(s):

DECISION ID | 21985 | Region 6
Cedar Creek

Pollutant: | Sediment
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d)list under section 3.10 of the Listing Policy, which deals with trends in water quality. One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It includes seven suspended sediment concentration values and six suspended sediment load values calculated from instantaneous discharge measurements. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Listing Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21985, Sediment | Region 6
Cedar Creek
LOE ID: | 4830
Pollutant: | Sediment
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 7 suspended sediment samples over 3 years under the Region 6 SWAMP program and did six loading calculations based on concurrent flow data. The average suspended sediment concentration of 7 samples was 32.8 mg/L; the average suspended sediment load in 6 samples was 1.36 tons/day. There is insufficient information available to document the normal range of suspended sediment loads and concentrations, to assess whether the sediment regime has been altered, or to assess effects on beneficial uses.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide narrative objective for suspended sediment states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Seven suspended sediment samples were collected over 3 years (2-3 samples/year, 2003 to 2005). Six loading calculations were done over 3 years (1 to 3 calculations/year). Temporal representation is inadequate to permit assessment of background conditions, alterations, or effects on beneficial uses.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20954 | Region 6
Cedar Creek

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence, from different datasets are available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. No quality assurance information was submitted with the second dataset. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples and the single USBLM sample do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of eight samples in one line of evidence exceeded the water quality objective. The single sample in the second line of evidence did not exceed the objective. The two lines of evidence are not being grouped because because different equipment may have been used in the two studies. The number of exceedances does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20954, Specific Conductance | Region 6
Cedar Creek
LOE ID: | 5383
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one specific conductance measurement in 2002. Specific conductance was 63 uS/cm. The MCL was not exceeded.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters designated for the Municipal and Domestic Supply use under the "Chemical Constituents" objective. The MCL for Specific Conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled.
Temporal Representation: | One measurement of specific conductance was made in 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. Chloride concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 20954, Specific Conductance | Region 6
Cedar Creek
LOE ID: | 4827
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey took 8 specific conductance measurements between 2003 and 2005 under the Region 6 SWAMP program. Specific conductance ranged from 149 to 245 uS/cm. An additional laboratorty measurement was 239 uS/cm. The MCL was not exceeded.
Data Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters designated for the Municipal and Domestic Supply use under the "Chemical Constituents" objective. The MCL for Specific Conductance is 900 microSiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight field measurements were taken over 3 years (2 to 3 samples/year between 2003 and 2005). A single laboratory measurement was also taken.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. Chloride concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21035 | Region 6
Cedar Creek

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. Two lines of evidence are available to support this decision; one consists of a single temperature measurement. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. No quality assurance information was submitted with the USBLM dataset. Because the SWAMP temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21035, Temperature, water | Region 6
Cedar Creek
LOE ID: | 5386
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one measurement of water temperature in Cedar Creek in August 2002. The temperature was 17 degrees Celsius.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The sections of the narrative temperature objective in the Lahontan Basin Plan that apply to Cedar Creek are as follows: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, "Upper Cedar Creek" was sampled.
Temporal Representation: | One temperature measurement was taken on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Management owns land in the lower watershed.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21035, Temperature, water | Region 6
Cedar Creek
LOE ID: | 4834
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured water temperature in Cedar Creek under the Region 6 SWAMP program. The temperature in 8 field measurements ranged from 3 to 16.5 degrees Celsius. Sampling frequency was inadequate to document the natural temperature regime or to show whether alterations have occurred.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The sections of the narrative temperature objective in the Lahontan Basin Plan that apply to Cedar Creek are as follows: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight temperature measurements were taken over 3 years (2003 to 2005). Temporal representation was inadequate to document the natural temperature regime (including diel, seasonal, and annual variations) or to show whether alterations have occurred.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 22007 | Region 6
Cedar Creek

Pollutant: | Total Dissolved Solids
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the Maximum Contaminant Level. The annual average site-specific water quality objective for TDS was exceeded in three of three years. . Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data use do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of the data exceeded the MCL. Three of three annual average datapoints exceeded the site-specific objective, and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22007, Total Dissolved Solids | Region 6
Cedar Creek
LOE ID: | 4838
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 8 samples for TDS between 2003 and 2005 under the Region 6 SWAMP program. Single sample concentrations ranged from 125 to 164 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for Total Dissolved Solids (TDS) is 500 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples were collected over 3 years (2 to 3 samples per year between 2003 and 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. TDS concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 22007, Total Dissolved Solids | Region 6
Cedar Creek
LOE ID: | 4837
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 8 samples for TDS between 2003 and 2005 under the Region 6 SWAMP program. Annual average concentrations exceeded the objective in 3 of 3 years. Single sample concentrations ranged from 125 to 164 mg/L.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific Total Dissolved Solids (TDS) objective for Cedar Creek (Lahontan Basin Plan Table 3-7) is an annual average of 100 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples were collected over 3 years (2 to 3 samples/year between 2003 and 2005). Three annual average calculations were done.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. TDS concentrations in the lower reach of the creek may be influenced by windblown salts from the dry lake bed.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21884 | Region 6
Cedar Creek

Pollutant: | Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological information is available to determine whether any of the Total Kjeldahl Nitrogen samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. There are no associated biological data to allow assessment of compliance with the objective for biostimulatory substances. 3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21884, Total Kjeldahl Nitrogen (TKN) | Region 6
Cedar Creek
LOE ID: | 6359
Pollutant: | Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek under the Region 6 SWAMP program. Concentrations of TKN in 8 quarterly samples ranged from 0.11 to 0.2 mg/L. No data on algae or macrophytes were available for assessment of compliance with the objective for biostimulatory substances.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include a site-specific objective for Total Kjeldahl Nitrogen (TKN) in Cedar Creek. (A separate line of evidence has been prepared for the site-specific objective for Total Nitrogen.) The narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight quarterly samples were collected over 3 years (2-3 samples/year, 2003 to 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21922 | Region 6
Cedar Creek

Pollutant: | Total Nitrogen as N
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence, from two different datasets, are available in the administrative record to assess this pollutant. One of three annual average datapoints exceeds the water quality objective. Annual averages were calculated from only two to three samples per year. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. The other does not. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples and the single USBLM sample do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. One of three annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21922, Total Nitrogen as N | Region 6
Cedar Creek
LOE ID: | 4829
Pollutant: | Total Nitrogen as N
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Cedar Creek between 2003 and 2005 under the Region 6 SWAMP program. Calculated concentrations of Total N in 8 samples ranged from 0.113 to 0.391 mg/L. The annual average objective was exceeded in one of three years.
Data Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective for total nitrogen in Cedar Creek is 0.2 mg/L (Lahontan Basin Plan Table 3-7).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight samples for the constituents of total nitrogen were collected over 3 years, with 2-3 sampling runs per year. Three annual average calculations were done.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21922, Total Nitrogen as N | Region 6
Cedar Creek
LOE ID: | 5372
Pollutant: | Total Nitrogen as N
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one sample in August 2002. The NO3-N concentration in one sample was 0.09 mg/L.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The site-specific objective for total nitrogen in Cedar Creek is 0.2 mg/L (Lahontan Basin Plan Table 3-7).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, "Upper Cedar Creek."
Temporal Representation: | One sample for nitrate nitrogen was collected in August 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Management owns land in the lower watershed.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 21944 | Region 6
Cedar Creek

Pollutant: | Turbidity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under sections 3.2 and 3.10 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Six lines of evidence, from two different datasets, are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared for data expressed as NTU and NTRU. The two types of units are measured differently and are not directly comparable. Four of the samples expressed as NTU (from two different datasets) exceed the California Maximum Contaminant Level. The Lahontan Basin Plan's narrative turbidity objective is a non-degradation objective, and sample numbers are insufficient to establish baseline conditions or detect trends as required under Listing Policy Section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of two datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. The other does not. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. The quarterly SWAMP samples and the single USBLM sample do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Three of 5 samples in the dataset with acceptable quality assurance exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. It is not possible to determine whether the narrative turbidity objective was exceeded because the requirements of Listing Policy Section 3.10 were not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 4836
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 5
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured turbidity between 2003 and 2005 under the Region 6 SWAMP program. Turbidity in 4 samples ranged from 2.4 to 26 NTU. An additional sample was below the detection level. The MCL was exceeded in three of the 5 samples reported as NTU.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California secondary MCL for turbidity is 5 Nephelometric Turbidity Units (NTU).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Five quarterly measurements of turbidity as NTU were taken between June 2004 and July 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 4835
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured turbidity in 203 and 2004 under the Region 6 SWAMP program. One of five quarterly measurements for turbidity expressed as NTU was below the detection level. The remainder of the samples ranged from 2.4 to 26 NTU. Sampling frequency was insufficient to document natural background conditions or allow detection of change.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable Lahontan Basin Plan objective for this watershed states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Five turbidity measurements expressed as NTU were taken between May 2003 and June 2004.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 5390
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 1
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management measured turbidity once in 2002. Turbidity was 6.9 NTU. This sample exceeded the MCL.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California secondary MCL for turbidity is 5 Nephelometric Turbidity Units (NTU).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, "Upper Cedar Creek", was sampled.
Temporal Representation: | One turbidity measurement was taken on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Managemetn owns land in the lower watershed.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 5389
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one turbidity measurement in 2002. Turbidity was 6.9 NTU.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The applicable Lahontan Basin Plan objective for this watershed states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | One turbidity measurement was taken in 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 7541
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured turbidity between 2004 and 2005 under the Region 6 SWAMP program. Two of three quarterly measurements for turbidity expressed as NTRU were below the detection level. The third measurement was 12 NTRU. Because NTU and NTRU are not directly comparable, this measurement is not in violation of the MCL.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California MCLs apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for turbidity is 5 NTU.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Three measurements of turbidity as NTRU were taken in October 2004 and April and July 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21944, Turbidity | Region 6
Cedar Creek
LOE ID: | 7540
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured turbidity between 2004 and 2005 under the Region 6 SWAMP program. Two of three quarterly measurements for turbidity expressed as NTRU were below the detection level. The third measurement was 12 NTRU. Sampling frequency was insufficient to document natural background conditions or allow detection of change.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable Lahontan Basin Plan objective for this watershed states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Three measurements of turbidity as NTRU were taken in October 2004 and April and July 2005.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21986 | Region 6
Cedar Creek

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: Three lines of evidence are available in the administrative record to assess this pollutant. For waters designated for the Cold Freshwater Habitat use, the objective is antidegradation based. The available data are insufficient to establish baseline conditions and assess trends as required under Listing Policy section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. One of the two datasets used satisfies the data quality requirements of section 6.1.4 of the Policy. The other does not. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the policy. The quarterly SWAMP samples and the single USBLM sample do not capture the diel, seasonal and annual variability expected in streamflows and pH in streams of the Lahontan Region. 3. The data used are insufficient to establish baseline conditions or to detect trends under the requirements of listing policy Section 3.10. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21986, pH | Region 6
Cedar Creek
LOE ID: | 4831
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured pH between 2003 and 2005 under the Region 6 SWAMP program. There were no violations of the 6.5 to 8.5 units objective in 8 field measurements and 1 laboratory measurement. (The field measurements ranged from 7.5 to 8.3 units and the laboratory measurement was 8.2 units.)
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The pH objective in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units." The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight field pH measurements were taken over 3 years (2 to 3 per year between 2003 and 2005).
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21986, pH | Region 6
Cedar Creek
LOE ID: | 5371
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management took one pH measurement in August 2002. The pH was 7.83 units. The objective was not violated.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The pH objective in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | The sample was collected at one station, "Upper Cedar Creek."
Temporal Representation: | One pH measurement was taken on August 13, 2002.
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest. The U.S. Bureau of Land Management owns land in the lower watersehd.
QAPP Information: | No information on quality assurance was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21986, pH | Region 6
Cedar Creek
LOE ID: | 4832
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured pH between 2003 and 2005 under the Region 6 SWAMP program. There were no violations of the 6.5 to 8.5 units objective in 8 field measurements and 1 laboratory measurement. (Field pH ranged from 7.5 to 8.3 units, and the laboratory measurement ws 8.2 units.) There are insufficient data available to characterize normal ambient pH levels and evaluate compliance with the 0.5 unit limit on pH changes.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The pH objective in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Cedar Creek near Cedarville.
Temporal Representation: | Eight field pH measurements were taken over 3 years (2 to 3 per year between 2003 and 2005). .
Environmental Conditions: | Cedar Creek is a tributary of Middle Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. The creek originates in the Warner Mountains, and most of its upper watershed is within Modoc National Forest.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):